Some baby changing pads and bedcovers such as, for example, mattress pads are typically designed to have a substantially waterproof major surface with the remaining major surface having at lest some moisture absorbency. Conventional pads, which are typically cotton/polyester pads having a waterproof major surface sealed thereto by a pinsonic technique, are disadvantageous for the reasons that the joining technique produces holes in the goods destroying the effectiveness of the water and/or moisture barrier and the seals formed through the use Of the aforesaid joining technique are extremely poor quality so that the cotton/polyester pad is incapable of withstanding as few as several washings without seriously degrading the seals.
It is also conventional to form such pads and join their plurality of layers by sewing the layers together. The sew lines form a stitched or quilted design. The latter design has the distinct disadvantage of not being waterproof and of being quite labor intensive and hence expensive to produce. In addition, the stitched pattern degrades after several washings and even a single defective stitch causes the entire stitched pattern to come apart.
The above disadvantages have been eliminated by invention of application Ser. No. 76,246 now U.S. Pat. No. 5,391,418 which provides a bed covering preferably in the form of a mattress pad having exposed major surfaces which are respectively substantially waterproof and moisture absorbent as well as being breathable. The structure further includes a mat-like layer of fibrous material preferably comprised of non-woven loosely held interengaging fibers which provide the pad with puffed or raised areas, each surrounded by the lines of the quilt pattern to yield an aesthetically pleasing quilted effect.
The webs forming the outer exposed major surfaces are bonded by way of an intermediate layer to create a unified end product in which the major surfaces are bonded together through an intermediary bonding web to form a finished product having all of the advantages of conventional pads as well as providing a highly serviceable end product capable of withstanding numerous washings without suffering any degradation.
The preferred embodiment is comprised of a plurality of webs which include, in the order of alignment, a waterproof web formed of a plastic material; and a pair of fibrous mats of non-woven material having a substantial loft and excellent moisture absorbency qualities and capable of forming a good bond with the waterproof web which serves as a bonding web for both outer layers.
A first web is preferably formed of a plastic material such as a vinyl or polyvinyl having the capabilities of providing a waterproof barrier (or at least a vapor barrier) and forming a bond capable of withstanding numerous washings without degrading the integrity of the bond or the webs.
The first web is preferably comprised of a vinyl such as, for example, a web comprised of at least one material selected from vinyl chloride polymer resins, thermoplastic polyester resins, vinylidene chloride polymer resins, polyamide resins and other materials having the properties of being waterproof and forming a good bond with the bonding web.
The non-woven outer layers are preferably formed of synthetic organic thermoplastic fibers having substantial loft to provide an aesthetically appealing quilted pad and forming a good bond with the adjacent webs. The bonds, as well as the mat, are capable of retaining the aforementioned characteristics even after numerous washings.
The waterproof layer is formed of a plastic material which softens and is sufficiently activated during the bonding process to form an excellent bond with the adjacent layers while at the same time retaining its integrity as a vapor barrier and preferably a waterproof barrier which further contributes to the aesthetically appealing high loft appearance of the quilted product due to the air captured between the moisture barrier and the absorbent layers.
The outer layers are preferably identical and are formed of a non-woven material of high quality and having good moisture absorption characteristics while at the same time forming a good bond with the vapor barrier. The fabric may be a blend of natural and synthetic fibers such as, for example, cotton and polyester. As an alternative, the fabric layer may be a non-woven fabric such as a viscose non-woven fabric.
The product may be produced in a substantially continuous fashion wherein each of the webs are wound about supply reels or the like and are introduced into dielectric heating apparatus in the form of continuous webs of indeterminate length which are superimposed one upon the other as they move through the heating apparatus.
The dielectric apparatus may be comprised of a platen electrode and a die electrode in the configuration of the pattern to be formed. The outer non-woven webs respectively engage the platen electrode and the die electrode. The die is mounted to reciprocate and is pressed into the aforementioned superimposed webs. High frequency electrical energy is coupled to the electrodes which dielectrically heat the materials pressed between the die and platen electrodes. The heating cycle is comprised of a sealing phase having a duration in the range from one to three seconds followed by a cooling phase of one to two seconds during which the electrodes and bonded webs are cooled by use of a coolant flowing through the electrode members and thereafter followed by a laminate advance phase of the order of 0.5 to one second during which time the die electrode is displaced from the platen electrode and the bonded webs are advanced, preferably by reciprocating gripper assemblies, through a distance sufficient to move beyond the electrodes and to introduce the next adjacent portions of the superimposed webs to the compression and heating cycle. The cooling cycle is utilized to set the bond and to prevent the waterproof web from sticking to the die electrode. As an alternative, the quilting pattern may be provided by a roller of suitable diameter so as to repeat the quilted pattern every eighteen inches or twenty-four inches, for example.
The dielectric heating apparatus provides electrical energy in the megacycle range with the dissipated energy being of the order of tens of kilowatts.
The product may, alternatively be provided with a fabric layer on both exposed surfaces thereof, the first web serving as both a waterproof layer as well as a bonding layer.
The product comprising the layers of material set forth hereinabove and being formed in accordance with the method steps described hereinabove exhibit all of the desired characteristics of conventional covers while providing the unique advantages of excellent moisture absorbency and waterproof qualities in an aesthetically appealing bed cover wherein the bonds joining the several webs comprising the product do not deteriorate even after repeated washing. Either outer surface may serve as the exposed surface of the product when placed on a bed or other supporting surface.
In order to provide the product with a greater appeal it is extremely desirable to enhance the aesthetic appearance of the product.